Great Barrier Reef Faces Huge Coral Decline, Global Insured Losses Reach $80 Billion in H1 2025

Strategic Insights -

The world's largest coral reef system, the Great Barrier Reef, has experienced its largest annual coral decline since records began, a report from the Australian Institute of Marine Science (AIMS) has found. AIMS surveyed the health of 124 coral reefs between August 2024 and May 2025, discovering that 48% of reefs underwent a decline in percentage coral cover. The primary reason for this decline is heat-stress driven by climate change, although tropical cyclones and crown-of-thorns starfish that eat coral also play a role in this significant decline.

In a separate development, global insured catastrophe losses reached $80 billion in the first half of 2025, according to Swiss Re Institute. This is above trend and makes the first half of 2025 the second costliest first half ever, after the earthquakes of Japan and New Zealand in 2011. The main drivers were the wildfires that swept through parts of Los Angeles in January, which alone accounted for close to 70% of the global insured losses in the first quarter. In total, Swiss Re estimates the combined insured losses for these wildfires at $40 billion, making this the most costly wildfire event ever.

Key Takeaways:

  • The Great Barrier Reef has experienced its largest annual coral decline since records began, with 48% of reefs undergoing a decline in percentage coral cover, primarily due to heat-stress driven by climate change.
  • Global insured catastrophe losses reached $80 billion in the first half of 2025, with the wildfires in Los Angeles being the main driver, resulting in $40 billion in combined insured losses.
  • The first half of 2025 is the second costliest first half ever, after the earthquakes of Japan and New Zealand in 2011, according to Swiss Re Institute.
  • The recent streak of global temperature records is over - for now, due to the recent decline in temperature, but climate change has not stopped, said Carlo Buontempo, Director of the European Union's Climate Change Service, Copernicus.
  • Despite China's significant renewable energy generation capacity, the nation's utilisation - how much of the energy is being used - is lagging, with the curtailment rate for solar power rising to 6.6% in the first half of 2025 and 5.7% for wind.

Statistics:

  • 48% of coral reefs experienced a decline in percentage coral cover, according to AIMS' report.
  • $80 billion in global insured catastrophe losses was reached in the first half of 2025, as reported by Swiss Re Institute.
  • The combined insured losses for the wildfires in Los Angeles was estimated at $40 billion by Swiss Re.
  • The first half of 2025 is the second costliest first half ever, according to Swiss Re Institute.
  • Last month was Earth's third-warmest July since records began, with an average temperature of 16.68degC, which is 0.45degC above the 1991-2020 average for the month.

Sources:

  • "Great Barrier Reef coral cover reaches record low" - Australian Institute of Marine Science (AIMS)
  • "Global insured catastrophe losses reach $80 billion in H1 2025" - Swiss Re Institute
  • "Swiss Re Institute says 2025 could be more expensive than 2021 and 2022, which were the two most costly, meteorological and climate-related disaster years ever:" - Swiss Re Institute